How much information on STD? HELP!!

Hi! Our travel agent is suggesting we get an idea of who is "really" interested in coming...we are trying to figure out a way to word that on the STD. Maybe have them email us...or put a comment on our Wedding Website..."Yes, we can't wait for more information" / "Unfortunately we'll see you when you return"...something along these lines...Has ANYBODY done this before??? H E L P!!!!